Direction of development of intelligent transportation systems (ITS) may be divided into vehicle communication technology and intelligent vehicle technology. Technologies for providing various services such as provision of real-time traffic information, warning for vehicle safety enhancement, messages for achieving smooth traffic flow and coordinated driving using vehicle communication have taken a major step forward according to development of vehicle communication. While development of intelligent vehicles improves convenience of a human-machine interface (HMI), vehicles equipped with various intelligent systems capable of reducing driver fatigue and aiding in safe driving appear owing to development of advanced driver assistance systems.
Vehicle-to-everything (V2X) refers to all types of communication methods applicable to roads and vehicles and represents a specific communication technology for realizing “connected vehicles” or “networked vehicles”. V2X networking is classified into three categories, that is, vehicle-to-infrastructure (V2I) communication, vehicle-to-vehicle (V2V) communication, and vehicle-to-pedestrian (V2P) communication. Vehicle-to-grid (V2G) which has recently emerged is expected to be added as another communication category in association with charging of electric vehicles.